As a long-term goal, a number of the newer environmental chemical carcinogens will be used together and with co-carcinogens to develop important models for study of human cancer of the colon. Initially, using methods with which others have prodced colon cancer, 1,2- dimethylhydrazine 2-HCl and methylazoxymethanol acetate will be given to CF1 mice under several conditions and via different routes of administration. Early changes in the colon and other organs will be examined by light and electron microscopy. While these experiments are in progress, detailed plans to study a variety of factors in the development and prevention of such tumors will be developed. The role of age and sex in experimental colon carcinogenesis will be studied. A transplantable colon cancer in CF1 mice will be developed for use by others and a tissue culture line of mouse colon cancer will be started.